Andes Project 2

09-12-2007

The
Andes Project

Abstract:

It has been proposed that focused incision might initiate
elastic and/or non-elastic rebound in association with an increase in the
depth of dissection. Uplift is then localized and recorded as permanent
deformation, which in turn, exerts a positive feedback on erosion. The
Eastern Cordillera of the Bolivian Andes represent such as situation of
focused erosional unloading. The morphometry of the La Paz drainage basin
can be considered to partly result from the feedback mechanism between
erosion and crustal bending. This feedback explains why all drainages beyond
the watershed disperse their waters to the Altiplano. It also provides an
explanation for the presence of the highest peaks just next to the location
where the La Paz River cuts into the bedrock across the Cordillera Real.
Finally, this feedback mechanism is considered to be responsible to inhibit
a headward shift of the section where bedrock incision is efficient.
However, it is unclear at the moment through which process, and at what
time, opening of the La Paz drainage and hence initiation of these feedback
mechanisms occurred.